Perry Mick wrote:

OK, what are the facts regarding coolant being flammable?
I tried to ignite some this morning with a bic lighter, no go.
More alarmism?

The vapors of glycol have a fairly low flash point.  I don't think the fluid
is very flammable.  Flash point is defined as the temperature of the fluid
in an open vessel when the vapors will ignite if a flame is passed over the
top of the vessel.  I tried this with pure propylene glycol a while back
'cause I couldn't believe it myself.  We had a good little weenie roast
going at a temp well below where we planned to operate (around 200 deg
somewhere...I really don't remember).  That was all fine and good until the
young machinist who was standing watch with the fire extinguiser decided to
put it out by shoving the snout of the FE right up to the vessel.  The FE
material (I forget which type) didn't have enough time to vaporize and was
dumped into the hot glycol as a liquid.  It then vaporized with a bang and
shot hot glycol all over the shop.  It was not one of my better days.
Luckily the fire was out and noone was hurt (as long as you don't include
pride)

Jeff Spitzer

Bill Freeman wrote:

Wow!   Sounds a bit "interesting".     Does this happen with ethylene
glycol, too?  Propylene glycol is the non-toxic coolant, which I have
never used, and might not want to.   Seems like another fine addition
to a coolant leak - FIRE !    I had always assumed (and you know what
that means) that coolant, which is half water would be non-flammable.
Sounds like another reason for aircooling, if 50-50 water-ethylene glycol
mix is flammable, as it sounds like it might be.

Bill
Long EZ builder & pilot
mechanical engineer

 
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